Glad to hear Boo is hanging in there. I hope you got some good suggestions from Dr. Lisa on the diet. And yes, I would not hesitate to use the phos binders, should you be attempting to feed other low phos FF, Wellness, or Merrick flavors or others like that. As you probably already know, once you start Calcitriol you really want to keep that phos number below 6 and the binders assist you in doing that. The one thing that snuck up on me with Willi early on with his CRF was the issue of constipation. Adding the binders can make some cats more prone to constipation, so started adding Miralax around that time. Keep us posted. Boo is lucky to have you.